Fusible Link Blows Before key turn key

[beebeecivic]

I have 1978 280z all stock. When i bought the car the po's song cut the wires off the ign switch. I got one from a ZX and wired it all up (not sure if its right because i am still a noob to schematics) So everything is all wired up, As soon as i turn the key to the "on" position the fusible link blows.

What can be the cause of this?

I have tried looking at grounds and all but i cant seem to find it

any input would be appreciated

[esprist]

I have 1978 280z all stock. When i bought the car the po's song cut the wires off the ign switch. I got one from a ZX and wired it all up (not sure if its right because i am still a noob to schematics) So everything is all wired up, As soon as i turn the key to the "on" position the fusible link blows.

What can be the cause of this?

I have tried looking at grounds and all but i cant seem to find it

any input would be appreciated

It is shorted to ground. Check al the wires for burn-marks especially stere area, and re-wrapped wires.

Esprist

[beebeecivic]

It is shorted to ground. Check al the wires for burn-marks especially stere area, and re-wrapped wires.

Esprist

Do you mean the grounds are shorting? are there any specific grounds i should be looking for?

And Stere is that the Steering column area comboswitch?)

[Mikes Z car]

One way to test is to hook a 12 volt light bulb or buzzer in place of where the fusible link is. That way you can disconnect wires until the light/buzzer stops going off, don't have to burn out a fusible link to test. Or, try disconnecting all the ignition switch wires and start with just the 12 volt input to the ignition switch and the 12 volt output as a starting point, maybe verify that much operation with a voltmeter and go from there.

[TomoHawk]

Are you sure that ZX ignition switch will work on your 1978? If you're new to schematics, how did you know it would work? The switch could bethe problem if you connected things that shouldn't be connected. Both wiring diagrams would be needed or a word from someone who knows the electrics for both cars.

[beebeecivic]

Are you sure that ZX ignition switch will work on your 1978? If you're new to schematics, how did you know it would work? The switch could bethe problem if you connected things that shouldn't be connected. Both wiring diagrams would be needed or a word from someone who knows the electrics for both cars.

To be honest i have no clue if its the same but when i looked at the back of both the switches they are the same such as B, IG, A, etc , etc. I Have both books and schematics to look at. I jus want someone to help me confirm this but the Z has one less wire (4 wires) on the switch compared to the ZX (5 wires)

And mike I am going to try that on tomorrow

So i just attach wires to a light bulb or just throw the bulb on top of the fusible link holder?

thanks again!

[TomoHawk]

At the odds & ends type stores, you might be able to get a test probe with the light already in it. Auto parts stores usually have stuff like that too. I even made a buzzer probe with a wire & clip on the one end and a metal probe of the other.

[beebeecivic]

At the odds & ends type stores, you might be able to get a test probe with the light already in it. Auto parts stores usually have stuff like that too. I even made a buzzer probe with a wire & clip on the one end and a metal probe of the other.

So its basically a contunity tester with alligator clamps on them?

thanks again!

[TomoHawk]

I built my buzzer-tester from cheap stuff from an electronics store (Radio Shack) and the junk box, and just mounted it to a tongue depressor with GOOP. It is handy for testing things which require one to turn on something that's too far away ( like a light switch, horns or relays) or in a blind area.

Don't forget to insulate the probe, except for the tip. You might even add a flat connector or flatten the tip to fit something like the ignition switch connector on a 280.

Edited June 22, 2009 by TomoHawk

[beebeecivic]

Sweet thanks again tomohawk!

[beebeecivic]

Yesterday I went and pulled all the fuses out and i found a 30 amp fuse in a 10 slot. I am going to replace it with the correct value and hope it will turn over

[beebeecivic]

So i did some more research via Google and found this

"When you turn the key to start, the ballast is bypassed, and the coil gets a full 12V to put out a hotter spark for starting. Releasing the key inserts the resistor back into the circuit to preserve the life of the points. Why not design the ignition to use 12V all the time? Well, nowadays they do but before 1975 or so that's the way points ignitions were designed. This means if you buy a high performance coil and simply install it, the ballast resistor may limit the new coil's power output. On a points distributor you can connect a wire across the ballast, it will route a full 12-14v to the coil and pick up some voltage, but it can shorten the life of the points."

Im not sure if the 78 280z has a ballast resistor or not but I am going to do more research

link: http://www.datsunzgarage.com/engine/